Bleaching compositions

ABSTRACT

PCT No. PCT/US95/04020 Sec. 371 Date Mar. 11, 1997 Sec. 102(e) Date Mar. 11, 1997 PCT Filed Mar. 30, 1995 PCT Pub. No. WO95/27776 PCT Pub. Date Oct. 19, 1995The use of anionic surfactants in a liquid peroxygen bleaching composition disclosed, for reducing itching of the skin, after it has come in contact with said compositions.

TECHNICAL FIELD

The present invention relates to a liquid bleaching compositioncomprising a peroxide bleach. The compositions are useful for a varietyof applications. The compositions are formulated so as to avoid itchingof the skin of the user using the composition, when it comes in contactwith the composition.

BACKGROUND

Bleaching with peroxygen bleaches is well known in the art. Peroxygenbleaching finds a variety of applications, such as bleaching fabrics or,in the household, treating hard surfaces or carpets. A major drawback ofliquid peroxygen bleaches is that they may bleach the skin of the personusing the composition and whiten it, if they come in contact with thecomposition. This whitening is fully reversible, but it also causestemporary itching of the skin.

It is thus an object of the present invention to provide a liquidperoxygen bleach composition which is formulated so as to avoid thistemporary itching phenomenon.

In response, it has now been found that the itching can be reduced byadding an effective amount of an anionic surfactant in said liquidperoxygen bleach composition.

SUMMARY OF THE INVENTION

Accordingly, in its broadest sense, the present invention is the use, ina liquid peroxygen bleaching composition, of an anionic surfactant toreduce itching of the skin of the user of said composition, after it hascome in contact with said composition.

In a preferred embodiment, the invention is a liquid compositionformulated as an emulsion comprising two phases, each phase comprising anonionic surfactant, said composition comprising a peroxygen bleach inone of said phases and an activator for said bleach in the other phase,said composition further comprising an anionic surfactant.

DETAILED DESCRIPTION OF THE INVENTION

The compositions according to the present invention are aqueous.Accordingly, the compositions according to the present inventioncomprise from 10% to 95% by weight of the total composition of water,preferably from 30% to 90%, most preferably from 60% to 80%. Deionizedwater is preferably used.

The compositions according to the present invention are stable aqueousemulsions of nonionic surfactants. By stable emulsion it is meant anemulsion which does not substantially separate into distinct layers,upon standing for at least 2 weeks at 50° C.

Said emulsions of nonionic surfactants comprise at least two nonionicsurfactants. In order to form emulsions which are stable said twononionic surfactants must have different HLB values (hydrophiliclipophilic balance), and preferably the difference in value of the HLBsof said two surfactants is at least 1, preferably at least 3. Byappropriately combining at least two of said nonionic surfactants withdifferent HLBs in water, emulsions according to the present inventionwill be formed.

The advantage of formulating the compositions of the present inventionas emulsions is that a stable activated bleaching compositions can beobtained where the bleach is present in the more hydrophilic phase, andthe activator for said bleach is present in the other more hydrophobicphase. Such emulsions are described for instance in EP 92 932.

Suitable nonionic surfactants for use herein include alkoxylated fattyalcohols. Indeed, a great variety of such alkoxylated fatty alcohols arecommercially available which have very different HLB values. The HLBvalues of such alkoxylated nonionic surfactants depend essentially onthe chain length of the fatty alcohol, the nature of the alkoxylationand the degree of alkoxylation. Hydrophilic nonionic surfactants tend tohave a high degree of alkoxylation and a short chain fatty alcohol,while hydrophobic surfactants tend to have a low degree of alkoxylationand a long chain fatty alcohol. Surfactants catalogues are availablewhich list a number of surfactants including nonionics, together withtheir respective HLB values.

The compositions according to the present invention comprise from 2% to50% by weight of the total composition of said hydrophilic andhydrophobic nonionic surfactants, preferably from 5% to 40%, mostpreferably from 8% to 30%.

The compositions according to the present invention may further compriseother nonionic surfactants which should however not significantly alterthe weighted average HLB value of the overall composition.

As an essential ingredient, the compositions herein comprise a peroxygenbleach. Suitable peroxygen bleaches for use herein are water solubleperoxygen bleach. Preferred for use herein is hydrogen peroxide, orwater-soluble sources thereof such as perborates, percarbonates,persilicates and persulfate salts.

Hydrogen peroxide is most preferred for use in the compositionsaccording to the present invention. Typically, the compositionsaccording to the present invention comprise from 0.5% to 20% by weightof the total composition of hydrogen peroxide, preferably from 2% to15%, most preferably from 3% to 10%.

By bleach activator, it is meant herein any compound which reacts withhydrogen peroxide to form a peracid. In the case of bleach activators,such hydrophobic bleach activators typically belong to the class ofesters, amides, imides, or anhydrides.

Suitable other activators herein must be hydrophobic in the sense thatthey will allow segregating said peroxygen bleach in a hydrophilic phaseand said bleach activator in a hydrophobic phase.

A particular family of bleach activators of interest in the presentinvention were disclosed in applicant's co-pending European patentapplication No 91870207.7. Particularly preferred in that family isacetyl triethyl citrate which was also disclosed in the context of barsoaps in FR 2 362 210. Acetyl triethyl citrate has the advantages thatit is environmentally friendly as it eventually degrades into citricacid and alcohol. Furthermore, acetyl triethyl citrate has a goodhydrolytical stability in the product upon storage and it is anefficient bleach activator. As used herein and unless otherwisespecified, the term bleach activator includes mixtures of bleachactivators.

The bleach activators herein cannot be a compound according to theformulae ##STR1## in which each of R^(a) and R^(b) represent hydrogen ora C₁ to a C₅ alkyl radical or a C₂ to C₄ alkenyl radical or a phenylradical, R^(a) and R^(b) being the same or different or combiningtogether to form a carbocyclic di-radical,

R^(c) represents hydrogen or a C₁ to C₅ alkyl radical or a phenylradical or is combined with R^(a) or R^(b) and the olefin group to forma carbocyclic radical,

R^(e) represents hydrogen or a C₁ to C₃ alkyl radical or a phenylradical,

n is 1 or 2,

when n=1, R^(d) represents hydrogen or a C₁ to C₃ alkyl radical or aphenyl radical,

when n=2, R^(d) represents a C₂ to C₁₀ alkylene di-radical or aphenylene di-radical,

and m is an integer from 0 to 8, or being one of the correspondingcompounds to those in formula (i) when n=2 or formula (ii) in which onlyone of the two enol groups or carboxylic acid groups, as the case maybe, is esterified.

Formulating the compositions according to the present invention in anacidic pH range contributes to the stability of the composition. Thecompositions of the present invention accordingly have a pH as is offrom 0.5 to 6, preferably of from 1 to 5. The pH of the composition canbe trimmed by all means available to the man skilled in the art.

As discussed hereinafter, when a liquid peroxygen bleach comes incontact with the skin of the person using it, it causes the itching ofthe skin. After a while, and even if the skin is rinsed there developsan irritation of the skin (herein referred to as itching) which isbelieved to be caused by the adsorption of the bleach on the user'sskin. This adsorption is believed to be induced by the prior adsorptionof the nonionic surfactants herein on the skin.

The finding underlying the present invention is that anionic surfactantswill reduce or even eliminate the itching which is caused by contact ofthe bleaching composition with the skin of the user of the composition.Accordingly, the compositions herein comprise an anionic surfactant, ormixtures thereof. Suitable anionic surfactants for use herein includealkyl sulfates, alkyl alkoxylated sulfates and others.

Suitable alkyl sulfate surfactants for use herein are water solublesalts or acids of the formula ROSO₃ M wherein R preferably is a C₁₀ -C₂₄hydrocarbyl, preferably an alkyl or hydroxyalkyl having a C₁₀ -C₂₀ alkylcomponent, more preferably a C₁₂ -C₁₈ alkyl or hydroxyalkyl, and M is Hor a cation, e.g., an alkali metal cation (e.g., sodium, potassium,lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-,and trimethyl ammonium cations and quaternary ammonium cations, such astetramethyl-ammonium and dimethyl piperdinium cations and quaternaryammonium cations derived from alkylamines such as ethylamine,diethylamine, triethylamine, and mixtures thereof, and the like).Typically, alkyl chains of C₁₂₋₁₆ are preferred for lower washtemperatures (e.g., below about 50° C.) and C₁₆₋₁₈ alkyl chains arepreferred for higher wash temperatures (e.g., above about 50° C.).

Suitable alkyl alkoxylated sulfate surfactants for use herein are watersoluble salts or acids of the formula RO(A)_(m) SO₃ M wherein R is anunsubstituted C₁₀ -C₂₄ alkyl or hydroxyalkyl group having a C₁₀ -C₂₄alkyl component, preferably a C₁₂ -C₂₀ alkyl or hydroxyalkyT, morepreferably C₁₂ -C₁₈ alkyl or hydroxyalkyl, A is an ethoxy or propoxyunit, m is greater than zero, typically between about 0.5 and about 6,more preferably between about 0.5 and about 3, and M is H or a cationwhich can be, for example, a metal cation (e.g., sodium, potassium,lithium, calcium, magnesium, etc.), ammonium or substituted-ammoniumcation. Alkyl ethoxylated sulfates as well as alkyl propoxylatedsulfates are contemplated herein. Specific examples of substitutedammonium cations include methyl-, dimethyl-, trimethyl-ammonium andquaternary ammonium cations, such as tetramethyl-ammonium, dimethylpiperdinium and cations derived from alkanolamines such as ethylamine,diethylamine, triethylamine, mixtures thereof, and the like. Exemplarysurfactants are C₁₂ -C₁₈ alkyl polyethoxylate (1.0) sulfate, C₁₂ -C₁₈E(1.0)M), C₁₂ -C₁₈ alkyl polyethoxylate (2.25) sulfate, C₁₂ -C₁₈E(2.25)M), C₁₂ -C₁₈ alkyl polyethoxylate (3.0) sulfate C₁₂ -C₁₈ E(3.0),and C₁₂ -C₁₈ alkyl polyethoxylate (4.0) sulfate C₁₂ -C₁₈ E(4.0)M),wherein M is conveniently selected from sodium and potassium.

Other anionic surfactants useful for detersive purposes can also be usedherein. These can include salts (including, for example, sodium,potassium, ammonium, and substituted ammonium salts such as mono-, di-and triethanolamine salts) of soap, C₉ -C₂₀ linearalkylbenzenesulfonates, C₈ -C₂₂ primary or secondary alkanesulfonates,C₈ -C₂₄ olefinsulfonates, sulfonated polycarboxylic acids prepared bysulfonation of the pyrolyzed product of alkaline earth metal citrates,e.g., as described in British patent specification No. 1,082,179, C₈-C₂₄ alkylpolyglycolethersulfates (containing up to 10 moles of ethyleneoxide); alkyl ester sulfonates such as C₁₄₋₁₆ methyl ester sulfonates;acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenolethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates,isethionates such as the acyl isethionates, N-acyl taurates, alkylsuccinamates and sulfosuccinates, monoesters of sulfosuccinate(especially saturated and unsaturated C₁₂ -C₁₈ monoesters) diesters ofsulfosuccinate (especially saturated and unsaturated C₆ -C₁₄ diesters),acyl sarcosinates, sulfates of alkylpolysaccharides such as the sulfatesof alkylpolyglucoside (the nonionic nonsulfated compounds beingdescribed below), branched primary alkyl sulfates, alkyl polyethoxycarboxylates such as those of the formula RO(CH₂ CH₂ O)_(k) CH₂ COO--M⁺wherein R is a C₈ -C₂₂ alkyl, k is an integer from 0 to 10, and M is asoluble salt-forming cation. Resin acids and hydrogenated resin acidsare also suitable, such as rosin, hydrogenated rosin, and resin acidsand hydrogenated resin acids present in or derived from tall oil.Further examples are given in "Surface Active Agents and Detergents"(Vol. I and II by Schwartz, Perry and Berch). A variety of suchsurfactants are also generally disclosed in U.S. Pat. No. 3,929,678,issued Dec. 30, 1975 to Laughlin, et al. at Column 23, line 58 throughColumn 29, line 23 (herein incorporated by reference).

Preferred surfactants for use in the compositions herein are the alkylbenzene sulfonates, alkyl sulfates, alkyl alkoxylated sulfates, andmixtures thereof.

In order to provide the desired benefit of reducing skin itching, wehave found that the anionic surfactant, or mixtures thereof should bepresent in a weight ratio of total anionic surfactant to total peroxygenbleach of from 1 to 10, preferably from 1 to 5, most preferably from 1to 3. It is believed that this benefit of reducing skin itching is dueto the formation of liquid crystals that limit the adsorption of thenonionic surfactant on the skin, and as a consequence, adsorption of thebleach.

Another surprising benefit obtained from the presence of anionicsurfactants is that they act as rheology modifyer in the emulsionsaccording to the present invention. Indeed, adding anionic surfactantsincreases the viscosity of the composition and that is desirable forseveral reasons, including control of pouring, control for spreading forinstance when the composition is used as a laundry pretreater, cling onvertical surfaces, when the composition is used as a hard surfacetreating composition.

However, adding anionic surfactants above a critical value which dependson the specific system used leads to phase separation and viscositycollapse. We have found that this viscosity building effect of anionicsurfactants herein also enhances the stability of the present emulsionsat higher temperatures (e.g. above 50° C.). Generally, the compositionsherein comprise at most 10% of anionic surfactant.

The compositions according to the present invention may further comprisea variety of the ingredients such as perfumes, dyes, opticalbrighteners, builders and chelants, pigments, enzymes, dye transferinhibitors, solvents, buffering agents, radical scavengers and the like.

The composition according to the present invention are particularlysuitable as laundry pretreaters, carpet cleaners, or laundry bleachadditives. In fact, it appears that the addition of anionic surfactantsimproves absorbance of the compositions of invention on the fibres. Thisdoes not improve pretreatment performance, but gives significant throughthe wash performance improvement, particularly on whiteness, dingycleaning and enzymatic stain removal.

In its broadest sense, however, the present invention is not limited tothe emulsions compositions of the present invention. Accordingly, thepresent invention also encompasses the use of an anionic surfactant, ina liquid peroxygen bleach composition, to reduce itching of the skin ofthe user of said compositions when it comes in contact with saidcomposition.

The present invention further encompasses a process for the manufactureof the composition described herein. The process according to thepresent invention comprises at least three steps:

In the first step, a hydrophobic mixture is prepared which comprises themost hydrophobic nonionic surfactant together with other hydrophobicingredients which are to be formulated in the composition, i.e. thebleach activator and optionally as perfumes, solvents, enzymes, bleachactivators and polymers.

In the second step, a hydrophilic mixture is prepared which comprises atleast water, the more hydrophilic nonionic surfactant. Said peroxygenbleach dyes, optical brighteners, builders, chelants, hydrogen peroxideand buffering agents. In this second step said peroxygen bleach ispreferably added last, after said buffering agent has been added.

Naturally, said first and said second steps can be performed in anyorder, i.e second step first is also suitable.

In the third step, both of said mixtures are mixed together.

The present invention will be further illustrated by the followingexamples.

EXAMPLES

The following compositions are made by listing the following ingredientsin the listed proportions

    ______________________________________    Ingredient        A         B    ______________________________________    Dobanol ® 45-7                      6.0       6.0    Dobanol ® 91-10                      3.0       3.0    Dobanol ® 23-2                      6.0       6.0    Alkyl sulfate     2.0       2.0    Hydrogen peroxide 6.0       7.5    Acety triethy citrate                      3.5       7.0    Citric acid       up to pH 4.0                                up to pH 4.0    Minors and deionized water                      balance   balance    viscosity 20° C., 50 rpm)                      700-900 cps                                700-900 cps    ______________________________________

    ______________________________________    Ingredient        C         D    ______________________________________    Dobanol ® 45-7                      8.0       6.7    Luthensol ® TO3                      7.0       8.3    Na Alkyl sulfate  2.0       2.0    Hydrogen peroxide 6.0       7.5    Acety triethy citrate                      3.5       7.0    Citric acid       up to pH 4.0                                up to pH 4.0    Minors and deionized water                      balance   balance    viscosity 20° C., 50 rpm)                      1000 cps  2000 cps    ______________________________________

Furthermore, a test was conducted on 80 panelists to evaluate the skinitching reduction phenomenon. The panelists were asked to usecomposition C, with and without Na alkyl sulfate, as a stain pretreateron fabrics. The panelists therefore used the product rubbing orspreading it with their fingers. They were asked whether they noticedthe skin itching problem.

The following results were observed:

    ______________________________________                                 composition with                 composition without NaAS                                 2% NaAS    Panelist Base: 80                 %               %    ______________________________________    Noticed skin itching                 41              22    when using the product    Claimed do not like the                 18              11    product because it causes    skin itching    ______________________________________

Also, the viscosity building effect of anionic surfactants was evaluatedby measuring the viscosity as a function of the amount of anionicsurfactant present in the composition. The following results wereobserved:

    ______________________________________           Composition                     Composition                               Composition           C without C with    C with  Composition C           NaAS      1.0% NaAS 2.0% NaAS                                       with 3.0% NaAS    ______________________________________    viscosity            800       3700      5000   viscosity    (cps) at                           collapses with    20° C.                      phase separation    at 50 rpm                          after 24 hrs at                                       room temperature    viscosity           8000      47000     65000   viscosity    (cps) at                           collapses with    20° C.                      phase separation    at 3 rpm                           after 24 hrs at                                       room temperature    ______________________________________

What is claimed is:
 1. A method of bleach pretreatment of fabrics byhand with a peroxygen bleaching composition wherein the itching effectof peroxygen bleach on skin is reduced, the said method comprising thestep of rubbing or spreading onto the fabric, with the fingers, a liquidperoxygen bleaching composition which is formulated as an emulsioncomprising two phases, each phase comprising a nonionic surfactant, saidcomposition comprising said peroxygen bleach in one of the phases, andan activator for said bleach in the other phase, with the proviso thatsaid activator is not a compound according to the formula. ##STR2## inwhich each of R^(a) and R^(b) represent hydrogen or a C₁ to a C₅ alkylradical or a C₂ to C₄ alkenyl radical or a phenyl radical, R^(a) andR^(b) being the same or different or combining together to form acarbocyclic di-radical,R^(c) represents hydrogen or a C₁ to C₅ alkylradical or a phenyl radical or is combined with R^(a) or R^(b) and theolefin group to form a carboxyclic radical, R^(e) represents hydrogen ora C₁ to C₃ alkyl radical or a phenyl radical, n is 1 or 2, when n=1,R^(d) represents hydrogen or a C₁ to C₃ alkyl radical or a phenylradical, when n=2, R^(d) represents a C₂ to C₁₀ alkylene di-radical or aphenylene di-radical, and m is an integer from 0 to 8, or being one ofthe corresponding compounds to those in formula (i) when n=2 or formula(ii) in which only one of the two enol groups or carboxylic acid groups,as the case may be, is esterified, said composition further comprisingan anionic surfactant wherein the ratio of said anionic surfactant tototal peroxygen bleach is from 1 to 10, with the proviso that the saidanionic surfactant be present in an amount less than that which willcause viscosity loss and phase separation.
 2. The method of claim 1where said peroxygen bleach is hydrogen peroxide.
 3. The method of claim2 where said hydrogen peroxide is present in an amount of from 0.5% toabout 20% by weight of the total composition.
 4. The method of claim 3where said hydrogen peroxide is present in an amount of from about 2% toabout 15% by weight of the total composition.
 5. The method of claim 4where said hydrogen peroxide is present in an amount of from about 3% toabout 10% by weight of the total composition.
 6. The method of claim 1where said anionic surfactant and said peroxygen bleach are present in aweight ratio of from 1 to about
 5. 7. The method of claim 6 where saidanionic surfactant and said peroxygen bleach are present in a weightratio of from about 1 to about
 3. 8. The method of claim 1 where saidanionic surfactant is present in an amount of at most 10% by weight ofthe total composition.
 9. The method of any of one of claims 1 to 8wherein said anionic surfactant is an alkyl benzene sulfonate or analkyl sulfate.